Overbased sulfurized calcium alkylphenolate manufacture

ABSTRACT

A METHOD OF PREPARING OVERBASED SULFURIZED ALKYLPHENOLATE OF ANTIOXIDANT PROPERTIES IN HYDROCARBON LUBRICATING OIL COMPRISING FIRST HEATING A MIXTURE OF SULFURIZED NORMAL CALCIUM ALKYLPHENOLATE, CALCIUM OXIDE, ALKANOIC ACID OF FROM 2 TO 3 CARBONS, ALKOXYETHANOL OF THE FORMULA ROCH2CH2OH WHERE R IS ALKYL OF FROM 1 TO 4 CARBONS, AND LUBRICATING OIL AND SUBSEQUENTLY CONTACTING THE HEATED MIXTURE WITH CARBON DIOXIDE.

United States Patent Claims I g I ABSTRACT OF THE DISCLOSURE *method of preparing overbased sulfurized alkylphenolate of antioxidant properties in hydrocarbon lubricatin'g oil co'mprising first heating a mixture of sulfurized normal calcium alkylphenolate, calcium oxide, alkanoic acid of from 2 to 3 carbons, alkoxyethanol of the formula ROCH CH OH'whe're R is alkyl of from 1 to 4 carbons,

and lubricating oil and subsequently contacting the heated mixture with carbon dioxide.

7 BACKGROUND OF INVENTION Field of invention This invention is in the field of art relating to fluent compositions specialized and designed for the use of between two relatively moving surfaces in contact therewith for reducing friction therebetween and pre serving th su acel The lubricant compositions produced by the "at the invention contain a compound which has a calciiim component linked to a carbon through an q ygm M Prior art It is wellknown that lubricating oils tend to deteriorate under theiconditionsnof use in present,day-.;diesel and automotive engines with attendant formations ofsludge andlacquerand resinous materialswhichadhere to-the engine. parts, particularly the piston, rings, .gr'ooves and skirt thereby lowering, the operating efficiency-0f; the engine. ,To. counteract the formation of these deposits, certain-chemical additives havebeen found which when added to lubricating oils have the ability to, keep the deposit forming materials, suspended in ;oil so 'that the engine-is kept ,elean and in anefficient operation condition ,for extended periods of time, ,These agents are, known in theart as-fdetergentspr ,dispersants. Metal organiccompound s, are particularly useful in this respect. These metal organic compounds are considered to be effective because they providealkalinityato neutralize strong organic and inorganic acids and are capable of dispersing deposits and deposit precursors in the oil phase, Over-based sulfurized metal alkylphenolates have been found to be particularly effective dispersants in lubricating oi1s. a I Hereinbefore and hereinafter by the term overbased it is meant that the ratio of the number of equivalents of calcium moiety tothe number of equivalents of phenol moietyfijs greater than one, i.e., the calcium metal ratio is 'gre ater, than bne ln contrast, the equivalent ratio of calcium moiety to phenol moiety in sulfurized normal calcium alkylphenola'te is 1 :1, i.e., a calcium metal ratio of 1. f

The prior art teaches many methods of preparing overbased sulfurized alkylphenolates. In one prior procedure the manufacture of lubricating oil compositions containing overbased sulfurized calcium, alkylphenolate comprises introducing CO5 into amixture' of lubricating oil, a sulfurized normal calcium alkylphenolate at an elevated temperature, reacting the resultant mixture with ethylene 3,810,837 Patented May 14, 1974 is manufactured therein by heating together a mixture of lubricating oil, alkylphenol, calcium hydroxide, elemental sulfur and a glycol.

Another prior procedure calls for introducing CO into a mixture of lubricating oil, sulfurized normal calcium alkylphenolate, ethylene glycol or propylene glycol, calcium oxide or calcium hydroxide, a higher alkanol of 8 to 18 carbons and a dispersant, namely, an overbased alkaline earth metal hydrocarbon sulfonate.

Although these two methods produce satisfactory overbased sulfurized calcium alkylphenolates, they do have the disadvantage of requiring the use of ethylene glycol which is difiicult to remove from the final reaction mixture. The presence of residual glycol in the final product is undesirable since it tends to degrade the high temperature dispersant properties of the product. Further, in respect to glycol and calcium hydroxide to form the overbased salt. 7

The sulfurizednormal calcium alkylphenolate reactant one prior method, a sulfonate dispersant is required in the initial reaction mixture and the presence of this sulfonate in the reaction mixture undesirably adds to the cost and undesirably excludes the final product from all uses wherein a sulfonate dispersant is prohibited since the sulfonate dispersant will be carried over into the final product and is not readily subject to separation.

To overcome the foregoing deficiencies, another prior method called for sequentially contacting a sulfurized normal calcium alkylphenolate with a calcium alkoxyalkoxide such as calcium methoxyethoxide, preferably in the presence of an alkoxyalkanoil, and then hydrolyzing between about 20 and wt. percent of the overbased product. Although this latter method obviates the use of unattractive glycol, it does have the undesirable feature of consuming relatively expensive calcium 2-alkoxyalkoxide which is not recoverable.

I SUMMARY OF INVENTION with carbon dioxide.

DETAILED DESCPIPTION on THE INVENTION In more detail, the method of theinvention comprises heating amixture of a sulfurized normal calcium alkylphenolate usually having a sulfur content between about 0.5 and 12 wt. percent, a calcium content between about 1 and 8 wt. percent and a total base number between about 55 and 225 which is characterized by the theoretical formula:

calcium oxide, alkanoic acid of from 2 to 3 carbons, alkoxyethanol of the formula ROCH CH OH, and hydrocarbon lubricating oil medium and subsequently contacting the heated mixture with carbon dioxide to form a "lubeoil composition containing sulfurized calcium alkylphenolate characterized by the theoretical formula Q-nCaCO where Q represents said sulfurized normal calcium alkylphenolate, R is a monovalent saturated aliphatic hydrocarbon radical (alkyl) from 4 to 100 carbons, x is an average integer of from 1 to 4, y is an average integer of from to 10, R is alkyl of from 1 to 4 carbons and n 'is an average integer of 0.1 to 2 and higher. It is to be noted when n is 0.1 the overbased product is represented as having a calcium metal ratio of 1.1 and when n is l the calcium metal ratio is 2. The sulfur content of the overbased product is normally between about 0.5 and 12 wt. percent, the calcium content is between about 3.5 and 12 wt. percent and the calcium metal ratio is between about 1.5 and 2.5.

It is to be noted that x and y in the foregoing formulas defining the sulfurized calcium alkylphenolate are defined as average integers since sulfurized normal and sulfurized overbased calcium alkylphenolates in essence are a complex mixture of monosulfide and polysulfide or a mixture of polysulfide as theoretically defined. In any case, the R group is mainly in the para position with the sulfur links mainly in the ortho position. Further, there is probably also a significant amount of covalent character to the calcium-oxygen bond.

"During the CO contact the CO gas is introduced directly into the heated mixture, preferably by blowing therethrough. The heating of the mixture is advantageously conducted at a temperature between about 100 and 250 0, preferably between 150 and 200 C., and the CO contacting is conducted at a temperature of between about 100 and 250 C., preferably between about 150 and 225 C. In respect to ingredient quantities, a mole ratio of calcium oxide to sulfurized normal calcium alkylphenolate is desirably between about 1:1 and 3:1, preferably between 1:1 and 1.5 :1, the mole ratio of calcium oxide to acetic acid is between about 2:1 and 30:1, preferably between 2.5 :1 and 12:1, the mole ratio of calcium oxide to alkoxyalkanol is between about .02:1 and 0.3:1, preferably between .04:1 and 02:1 and the mole ratio of CO to calcium oxide is at least about 1:1 and up to 4:1 and higher, preferably between about 1:1 and 1.521. The

lubricating oil medium can constitute between about 10 and 90 wt. percent of the reaction mixture, desirably between about 30 and 70 wt. percent resulting in a final lubricating oil medium can constitute between about 10 based calcium salt concentrate of between about 10 and 90 wt. percent, preferably between about 30 and 70 wt. percent.

Under advantageous conditions, the heated reaction mixture prior to CO contact is heated to a temperature within the contemplated temperature under reduced pressure, if necessary, to insure the removal of the alkoxyethanol ingredient as overhead. Further, under advan- "tageous conditions, an inert gas such as nitrogen is passed through the reaction mixture during the heating stage and also advantageously after CO contact. The inert gas rate is suitably between about 1 and 10 volume gas/ volume liquid mixture/hour. Further, the heating stage is normally conducted for a period of between about 1 and 5 hours and the CO contact stage between about 1 and 3 hours.

The crude product may be purified by standard means such as by blowing the final product with inert gas to remove volatile by-products and unreacted reactants and filtering the blown mixture through a standard pressure filter plate at about 20 to 200 C. under about 0.1 and 100 psi. pressure utilizing a diatomaceous earth filter aid.

Under preferred conditions, the reaction mixture is maintained in an agitated state to facilitate ingredient contact. Usually, such state is maintained by the passage of carbon dioxide and inert gas th rethrough but if need be stirring may be instituted for supplemental agitation.

In the method of the invention there are several material aspects:

In the first place, it is essential that both the alkanoic acid and alkoxyalkanol in addition to the other method ingredients as defined be employed otherwise essentially no overbasing occurs. Further, the aforementioned temperature ranges and quantity ranges are required in' order to obtain satisfactory overbasing in the desired range.

As heretofore indicated the products of the claimed method are lube oil concentrates of the overbased sulfurized calcium alkylphenolate wherein the overbased alkylphenolate content is between about 10 and Wt. percent. In finished lubricating oil compositions ready for automotive use, the overbased additive content is advantageously between about 0.1 and 10 wt. percent, and therefore, the final product is normally subjectto-additional dilution with hydrocarbon lubricating oil before use. In the finished lubricating oil compositions suitable for use in automotive engines, additives in addition to the overbased sulfurized calcium alkylphenolates may be included. These other additives ma be any of the standard suitable pour depressors, additional sludge dispersants (e.g., petroleum sulfonates), antioxidants, silver corrosion inhibitors, viscosity index improvers and oiliness agents. Exactly what other additives are included in the finished oil and the particular amounts thereof will, of course, depend on the particular use and conditions desired for the finished oil product.

Suitable base oils useful in the manufacture of the overbased phenolates include a wide variety of hydrocarbon lubricating oils such as naphthenic base, parafiinic base and mixed base mineral oils of other hydrocarbon lubricants, e.g., lubricating oils derived from coal products and synthetic oils, e.g., alkylene polymers such as polypropylene and polyisobutylene of a molecular weight between about 250 and 2500. Advantageously, lubricating base oils having an SUS viscosity at F. between about 50 and 2000, preferably between about 100 and 300 are employed.

Examples of the sulfurized calcium alkylphenolate reactants based on the theoretical formula:

o 0- o- Y Y I' I I l l 81 L@ T@ are where R is 4-octyl, x is l and y is 0; R is 4-dodecyl, x is 1 and y is 1; R is 4-eicosyl, x is 2 and y is 2; R is 4-dodecyl, x is 2 and y is 3; and mixtures thereof. It is to be noted that x and y are defined as average integers. Further description and method of preparing sulfurized normal calcium alkylphenolates are set forth in U.S. 3,528,971 and 3,549,534. Briefly, the normal salt reactants are prepared by reacting an alkylphenol characterized by the formula Example I This example illustrates the method of the invention.

A mixture of 13 grams (0.23 mole) of calcium oxide, 1.2 grams (0.02 mole) of acetic acid and 500 mls. (6.4 moles). of 2-methoxyethanol were refluxed (128 C.) for a period of 3 hours during which time nitrogen gas was continually passed therethrough at a rate of 50 mls./

minute. To the resultant refluxed mixture there were added 20 grams of naphthenic lubricating oil having an SUS viscosity of about 100 at 100 F. and 270. grams (approx. 0.2 mole) of a 50 wt. percent lube oil solution of sulfurized normal calcium-4-C +C alkylphenolate of a calcium ratio of 1, the lube oil solution having a calcium content of 2.85 wt. percent, a sulfur content of 3.3 wt. percent, a total base number of 80, the lube oil component being a naphthenic lubricating oil having an SUS viscosity of about 100 at 100 The resultant mixture was heated and stripped to 210 .C. with the heating continued at this temperature for a period of 2 hours. Nitrogen gas waspassed through the reaction mixture at a rate of 5 mls./minute. At the end of the 2 hour period the, nitrogen blowing was ceased and carbon dioxide was passed through the reaction mixture at a rate of..100 mls./minute for a period. of 1 hour at a temperature of 210 .C. representing an introduction of approximately 0.27 mole CO At theend of the 2 hourperiod, the resultantmixture was finally blown with nitrogen at a rate of 50 mls./minute for a period of lhour at 210 C. and the blown mixture was filtered through diatomaceous earth'at 150C. The filtered product was found to be a,

0 'wt..percent lubricating oil solution of. overbased sulfuri z ed calcium allrylphenolate having a metal .ratioof 2.0, the filtered product having a calciumcontent of 5.1 percent (5.4 calcd.), a total base number of 139,.(151

lled.) nd. asl ur co et of 18 Perm I Example II This example further illustrates' themethod oftheinf ventionn v A mixture was prepared consisting of 14 granis (0.25 mole) of calcium oxide, 6" grams (0.1 'mole')of acetic acid, 201grams:of naphthenic-lubricating oil of "an'SUS viscosity of about 100vat 100 F.,'200 mls. (2.5 moles) .of- Z-methoxyethanoland 270 grarns-(approx. 022 mole) of a 50 wt. percent lube oil solution of sulfurizedfnormal calcium-4-C +C alkylphenolate of a calcium metal ratio of 1, said lube solution having a calcium content of 2.85 wt. percent, a sulfur contentof 3.3 wt. percent, a total base .numberof 80, theoil component being naphthenic oil. of an SUS viscosity of 100 at 100 F. The mixture .was refluxed for 3 hours at 128 C. while passing nitrogen gas therethrough at a r'ate of 50 mls./minute. At the end of the 3 hour period, the reaction mixture was heated to 210 C. with the continued nitrogen blowing to-stripoff Z-methoxyethanol and the 210 C. temperature was maintained for'xa 4 hour- -period. At theend' of'the 4 hour per-iodthe nitrogen blowing was ce'asedand carbon dioxidew-was passed through' the mixture for 1' hour at'a rate oi- 1 00*m1s./minute for a total introduction of 0.27 mole followed by nitrogen blowing at the previous nitro-- gen rate for 0.5 hour-awhile maintaining the temperature at 210 C.;.Therresultant product wasfiltered through diatom aceousearth and the clarified filtrate was determined to be a 50 wt. percent lube oil solution of overbased sulturized calcium 4-C +C .alkylphenolate of a calcium metal ratio of 2.1, the solutionhaving a calcium content of 5.3 wt. percent (5.7 wt. percent calcd.), a sulfur content of 2.8 wt. percent and a-total base number of 141 (159 calcd.).

ma -1. m.

This example illustrates that overbasing will essentially not occur in the absence of the alkanoic acid ingredient.

There was formed a mixture of 21"grams (0.37 mole) of calcium oxide, 18 mls. (1.0 mole) of water, mls'. (1.3 moles) of Z-methoxyethanol, 22 grams of naphthenic lubricating oil of an SUS viscosity of about 100 at 100 F.', and 200 grams (0.15 mole) of a 50 wt. percent lube oil solution containing normal sulfurized calcium-4 C b -l-C alkylphenolate of a calcium metal ratio of 1, said solution having a calcium content of 2.95 wt. percent, a sulfur content of 2.7 wt. percent, the oil component being a naphthenic oil of an SUS viscosity of 100 at 100 "F. The

mixture was nitrogen stripped and CO blown asinE'x Example IV 'This example further illustrates that essentially no overbasing occurs in the absence of the alkanoic acid.

ingredient.

"A mixture was formed consisting of 14 grams (0.25 mole) of calcium oxide, 200 mls. (2.5 moles) of 2-methoxyethanol; 20 grams naphthenic lubricating oil of an SUS'vi'scosity of about 100 at 100 F., and 270 grams (about 0.2 mole) of a 50 wt. percent lube oil solution of sulfurized normal calcium 4-C -l-C alkylphenolate of'acalciur'n metal ratio of 1, said solution having a calcium content of 3 wt. percent, a sulfur content of 2.9 wt. percent, a total base number of 86, the lube oil component being naphthenic oil of an SUS viscosity of about 100'at- 100 F. The mixture was refluxed'fora period "of"3 hours at 127 C. while passing nitrogen gas therethrough" at a rate of 50 mls./minute. It was then heated to 210 C.with continuousnitrogen blowing with stripping oft the Z-methoxyethanol. It washeld at'210 Cliffor'fh period of 4 hours. At the end of the 4 hour period "and at "210 C. there was passed through the mixture for 1 hour 100 mls./minute of CD5 or a total of 0.27"mole CO followed by nitrogen blowing at the previous nitrogen rate fora 0.5 hour period while keeping the temperature at 210 C. The product was filtered through idiatomaceous earth. The clarified product upon analysis was found to be a 50 wt. percent lube oil solutionof essentially sulfurized normal calcium-4-C +C alkylphenolate, said phenolate having a calcium metal ratio of about 1.2, said solution having a calcium content. of 3.4 wt; percent (5.7 wt. percent calcd.), a sulfur content of 3 wt. percent and a total base number of 96 (1'59 calcd.), thereby demonstrating that only minimal overbasingoccur'red.

. Example V This example illustrates the failure of satisfactory overbased product formation with the substitution of the alkoxyethanol ingredient with closely related ethylene glycol.

There was formed a mixture of 14 grams (0.25 mole) of calcium" oxide, 6 grams (0.1 mole) of acetic acid, 20 grams of naphthenic lubricating oil of an SUS viscosity of 100 at 100 F., 200 mls. (3.6 moles) ethylene glycol, and 270 grams of a 50 wt. percent lube oil solu- '7 tion of sulfurized normal calcium alkylphenolate of a calcium metal ratio of about 1, said solution having a calcium content of 2.90 wt. percent, a sulfur content of 3.0 wt. percent and a total base number of 80, the lube component being naphthenic lube oil of an SUS viscosity at 100 F. of 100. The resultant mixture was heated for 3 hours at 150 C. while passing a nitrogen therethrough at a rate of 50 mls./minute. At the end of the 3 hour period, carbon dioxide'was then passed through the mixture-for 1 hour at a rate of 100 mls./minute representing a total carbon dioxide introduction of 0.27 mole and then nitrogen was introduced for a period of .1 hour at arate of 50 mls./ minute while maintaining the temperature at 150 C. At the end'of the 1 hour period the reaction mixture was heated to 210 C. under a reduced pressure .of 15 mm.-Hg while removing ethylene glycol as overhead and held at this temperature for a 1 hour period. The product was filtered through diatomaceous earth. The product was unstable in that signicant quantities of calcium containing solids continually settled out of it. The foregoing indicates that a stable Example VI This example illustrates the failure of overbasing to take place in the absence of the alkoxyethanol ingredient.

There was formed a mixture of 13 grams (0.23 mole) of calcium oxide, 6 grams (0.1 mole) of acetic acid, 20 grams of naphthenic lubricating oil of an SUSviscosity of 100 at 100 F. and 260 grams (0.2 mole) of a 50 wt. percent lube oil solution of sulfurized normal calcium alkylphenolate of a calcium metal ratio of about 1,- said solution having a calcium content of 3.0 wt. percent, a sulfur content of 3.3 wt. percent and a totalbase number of 80, the lube component being naphthenic lube oil of an SUS viscosity of 100 F. of 100. The resultant mixture was heated for 4 hours at 204 C. while passing a nitrogen therethrough at a rate of 50 mls./minute. At the end of the 4 hour period, carbon dioxide was passed through the mixture for 1 hour at a rate-013100 mls./ minute representing a total carbon dioxide introduction of 0.27 mole and then nitrogen was introducedfor a .period of 0.5 hour at a rate of 50 mls./minute while maintaining the temperature at 210 C. The product was filtered through diatomaceous earthand thezfiltrate analyzed. It wasdetermined to be a 50 wt. percentv lube ,oil solution of sulfurized normal calcium-4-Cm+C ,-al-

kylphenolate, said alkylphenolate per se having a calcium metal ratio of l, the solution having a calcium content of 2.8 wt. percent and a sulfur content of 3.1 wt. percent and a total base number of 78. The foregoing indicates that essentially no overbasing took place.

We claim:

. 1. A method of preparing a lubricating oil composition containing an overbased sulfurized. calcium alkylphenolate wherein said alkyl group is of from 4 to carbons consisting essentially of first heating a mixture of calcium oxide, an alkanoic acid selected from acetic acid or propanoic acid, alkoxyethanol of the formula ROCH CH OH where R is alkyl of from 1 to 4 carbons, a hydrocarbon lubricating oilof an SUS viscosity at 100 F. of between about 50 and 2000 and a sulfurized normal calcium alkylphenolate wherein said alkyl is as heretofore defined, at a first temperature of between about 100* and 250 C., subsequently introducing into the reaction mixture carbon dioxide in a total amount of at least about 1 mole per mole of said calcium oxide, at-a second temperature between about 100 and 250 C. and recovering said lubricating oil composition, in said mixture, said lubricating oil being present in a major amount, the initial mole ratio in said mixture of calcium oxide to acetic acid being between about 2:1 and 30:1, the initial mole ratio in said mixture of calcium oxide to said normal sulfurized calcium alkylphenolate being between about 1:1 and 3:1, the initial mole ratio of calcium oxide to alkoxyalkanol being between about .02:1 and 0.3:1.

2. A method in accordance with claim 1 wherein said acid is acetic acid and said alkoxyethanol is 2-methoxyethanol. I

3. A method in accordance with claim 1 wherein in said first heating and subsequent to said CO introduction an inert gas is passed through the reaction mixture at a rate of between about 1 to 10 vol. gas/vol. reaction mixture/hour.

4. A method in accordance with claim 1 wherein in said first heating said calcium oxide, said alkanoic acid and said alkoxyethanol is first heated at said first temperature followed by the subsequent introduction of said hydrocarbon lubricating oil and said sulfurized normal calcium alkylphenolate followed by the removal of said al-koxyalkanol as overhead. I

5. A method in accordance with claim 4 wherein said alkanoic acid is acetic acid and said alkoxyethanol is 2-methoxyethanol.

PATRICK P. GARVIN, Primary Examiner "A. H. METZ, Assistant Examiner U.S. c1. X.R. 2s2 1s, 40.7 

